This invention relates to modification of colorants during ink-jet printing, and, more specifically, to modification of colorants to reduce the intensity of the printed dye.
Traditionally, textile manufacturers have printed designs onto fabrics using screening techniques. A series of flat or rotary screens are produced with a multitude of holes through which the ink can pass through the screen onto the fabric. A different screen is required for each color. Furthermore, to print more than one color, the screens must be perfectly registered with one another. Thus, complex patterns composed of many colors are difficult to produce. If it is desired to alter colors within a pattern, the ink used with a particular screen can simply be changed. If an alteration to the pattern itself is desired, however, the manufacturer must produce a whole new set of screens. This process is expensive and may take many weeks to complete.
As a result, many manufacturers are adapting ink-jet printing techniques to print designs onto various fabrics. Changing the pattern on the fabric is as simple as altering the design on a computer. A new sample with the revised design may be printed almost immediately. Traditional ink-jet printers for paper utilize four pens: cyan, yellow, magenta, and black. Two additional pens, light cyan and light magenta, are frequently used to improve tonal quality. Even greater tonal quality and color gamut are required for industrial fabrics. At least eight to twelve pens are typically used in these applications. For example, six or seven primary colors, including red, blue, orange, gold, and green may be used in addition to the four basic colors. Light pens, including light cyan, light magenta, light blue, and light red may also be employed. The light pens are required for producing pastels and other lighter colors. To produce a light color with a dark pen, full strength colors are printed in a dithering pattern. While an observer standing far away would observe the pastel color, on closer observation, the customer would see the individual pixels of color instead of the overall design. Thus, light color inks are necessary to produce light color fabrics. However, ink-jet pens are relatively expensive, and the use of a large number of pens increases printing costs dramatically. As a result, it is desirable to have a printing method that can produce a range of color intensities with a minimal number of pens.
In one aspect, the invention is a method of printing with an ink-jet printer. A colorant and a deactivating agent are printed onto a substrate. The agent is caused to react with either the substrate or the colorant, and the substrate is washed.